Viruses free up organic matter so that
new life can be generated.
Aquatic
ecosystems
– Bacteriophag
es are
abundant in
fresh and
saltwater
– Bacteriophag
es free up
organic
matter so
that new life
.

Lytic Bacteriophages and Nutrient Cycling
.

Hershey-Chase
Blender
Experiment
Figure 01.
. It provided
evidence that DNA was
associated with the genetic
material of the
bacteriophage.05: Diagram
depicting the design of Alfred
Hershey and Martha Chase’s
experiment.

Pathogenesis..• Genome may be
infectious
Figure 01. Principles of Virology: Molecular Biology. S. and Control of Animal Viruses. 2003. Second Edition. ASM Press. et al.09A: Poliovirus RNA is infectious!
Infectious particles of poliovirus can be
produced even if only the genetic material
(RNA) of the virus is introduced into cells
growing in a culture dish.
Adapted from Flint.
.J.

J. Principles of Virology: Molecular Biology..
Pathogenesis. The integrated viral
genome is called a provirus. Second Edition. and Control of Animal Viruses.Retroviruses insert their
genome into cellular
chromosomes
Figure 01.
Adapted from Flint.
. S. 2003. et al.09B: Retroviruses can persist in cells by integrating their own DNA
(or a copy of their RNA) into the genome of the host cell. ASM Press.

Characteristics of Viruses
• Small (nm in size)
• Pass through filters that retain bacteria
• Completely dependent on the host cell
• Contain one species of nucleic acid
• Contain receptor-binding proteins
• Genome may be infectious
• Some viruses can persist by integrating their genome
into the cellular chromosom
.